Comprehensive process technology of solid waste in alumina plant

Abstract

The invention discloses a comprehensive process technology of solid waste in an alumina plant, belonging to the technical field of solid waste processing. The technology blends the solid waste after sand-extraction and iron-extraction or solid waste to directly with carbide slurry or milk of lime, liquid or solid caustic soda, follow-up alkali liquor and the like and mainly utilizes the digestionprocess with high temperature and high caustic ratio to change the slag phase of the red mud, so as to realize efficient recycling of alumina and sodium oxide and to realize systematic circulation bymating with sedimentation and separation, evaporation and concentration, crystallization separation of sodium aluminate and the like. The solid waste is red mud, tailings or low-grade aluminium ore in the aluminium plant. In the technology, the recovery rate of alumina in the solid waste can reach 60%-90% and the recovery rate of sodium oxide can reach over 90% with notable benefits; the alkali in the solid waste can be reduced to below 1%, reaching the basicity range of alkalis soil; after filter pressing, the invention can be used as soil directly without environmental protection risks, thus realizing waste resource utilization and environmental friendliness in deed.

Description

Technical field: [0001] The invention relates to a treatment technology for solid waste, in particular to a treatment process for solid waste produced by Bayer process alumina. Background technique: [0002] The stockpiling of solid waste produced in alumina plants not only occupies land and costs a lot, but also if the anti-seepage treatment is not good, the alkali in solid waste will cause serious adverse effects on the environment, especially groundwater, which is a major safety hazard in alumina production. Therefore, the accumulation of solid waste has always been a difficult problem for alumina manufacturers, and how to recycle it is imminent. At present, the solid waste treatment technologies used at home and abroad mainly include dry storage, gravity sand extraction for iron extraction, magnetization iron extraction, and processing of building materials. The treated solid waste cannot be directly used as raw materials for cement plants due to its high alkali content....

AI Technical Summary

Problems solved by technology

[0002] The stockpiling of solid waste produced in alumina plants not only occupies land and costs a lot, but also if the anti-seepage treatment is not good, the alkali in solid waste will cause serious adverse effects on the environment, especially groundwater, which is a major safety hazard in alumina production. Therefore, the accumulation of solid waste has always been a difficult problem for alumina manufacturers, and how to recycle it is imminent

At present, the solid waste treatment technologies used at home and abroad mainly include dry storage, gravity sand extraction for iron extraction, magnetization iron extraction, and processing of building materials. The treated solid waste cannot be directly used as raw materials for cement plants due to its high alkali content.

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